1. Field of the Invention
The present invention relates to air conditioning apparatus and more particularly to an improved method and apparatus for sub cooling liquid refrigerant before it is released to the evaporator through the expansion valve or other control device in an air conditioning system.
Known methods and apparatus for using condensate to cool liquid refrigerant are designed and built as an integral part of the air conditioning apparatus, and generally feature a heat exchanger coil located in the drain pan under the evaporator. These methods and apparatus introduce the problem of reintroducing heat and vapors created in the heat exchange process into the air conditioned space. In addition, a heat exchanger coil located in the drip pan complicates maintenance when cleaning or other maintenance procedures are required.
2. Description of Related Prior Art
U.S. Pat. No. 3,996,764 to Gilmer et al. discloses a window air conditioner wherein warm refrigerant is cooled in a cooling coil immersed in a separate reservoir of cold condensate before releasing the refrigerant to the evaporator. This method applies only to window air conditioners and must be designed and built into the window unit. There is no outside separate container the condensate water.
U.S. Pat. No. 2,722,809 discloses a refrigerator construction in which warm refrigerant is cooled by passing it through coils immersed in an open drip pan containing condensate. This apparatus is not applicable to a split system air conditioner.
U.S. Pat. No. 2,296,997 discloses a method wherein condensate is collected in a drip pan and is led therefrom to an open pan in which a coil containing warm refrigerant is immersed. This method requires extensive changes in piping and air flow and is aimed primarily at the disposal of condensate water.
U.S. Pat. No. 3,355,908 discloses a method for cooling refrigerant by passing it through a coil in a drip pan. This method has the disadvantage of reintroducing heat into the conditioned space. Furthermore, it is not an auxiliary device which can be added to an existing air conditioning system to improve efficiency.
U.S. Pat. No. 3,691,786 discloses a method for cooling liquid refrigerant which is not an auxiliary device and which, in spite of complicated design features, does not completely eliminate the reintroduction of heat into the air conditioned space.
U.S. Pat. No. 4,250,717 discloses the use of tap water and condensate water to cool a condenser coil and the compressor. This is essentially a water cooled condenser for an air conditioning system, not an auxiliary device for an air cooled system.
U.S. Pat. No. 4,370,864 discloses the use of condensates supplement tap water in a water cooled ice machine. The method is not applicable to air cooled air conditioning apparatus.